A gaze tracking system determines the direction an eye is looking at. A typical gaze tracking system uses a camera and a light source to acquire an image of the pupil and of a reflection from the cornea. Using the relative displacement of the corneal reflection with respect to the pupil enables a determination to be made of the gaze direction. Other methods, using optical and/or non-optical methods are also known. For example, other optical methods may track reflections from one or more of the surfaces of the lens of the eye. Non-optical methods may require the use of electrode patches placed near the eye, measuring potentials developed by the eye muscles as the eye changes its gaze direction. However, in many cases the measured gaze direction is relatively inaccurate. Specifically, systems that do not require the user to wear any device tend to be more inaccurate, and there is a need for an accurate gaze tracking system that does not require the user to wear anything.
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